Re: [RFC] RNG rewrite...

[Jeff Garzik <jgarzik@pobox.com>]

Deepak Saxena wrote:
> I want to add support for the RNG on Intel's IXP4xx NPU and 
> looking at the existing hw-random.c code, it is written with
> the assumption that the RNG is on the PCI bus. I can put a
> big #ifdef ARCH_IXP4XX in there but instead I would rather
> rewrite the damn thing to use the device model and have a rng
> device class with individual drivers for each RNG model, including
> IXP4xx. I'll keep the miscdev interface around but will add a
> new interface under /sys/class/rng that the userspace tools 
> can transition to. Is this OK with folks?

How does the hardware export RNG functionality?  CPU insn?  Magic memory 
address?  Can it be done 100% in userspace?


> One question I have is about the following comment:
> 
>  * This data only exists for exporting the supported
>  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
>  * register a pci_driver, because someone else might one day
>  * want to register another driver on the same PCI id.
> 
> Why? Is there something else on those IDs that another driver might
> care about?

They are bridge ids, not device ids.

	Jeff